DURHAM, N.C. — Early on the first day of this Brooklyn Nets training camp, as Shaun Livingston grinded through a battery of drills on the floor of the pristine gymnasium, the man for whom it’s named walked in, grabbed a chair, and studied a small piece of might’ve-been.

“You’re looking just like I remember,” Mike Krzyzewski said later, warmly.

“Coach,” Livingston said, laughing, “maybe if you’d had this beautiful building back in the day it would’ve gone different.”

Back in the day, back in 2004, Livingston was the jewel of that spring’s high school recruiting haul and Krzyzewski had him locked up. The old point guard out of Chicago’s Archbishop Weber High had lured the kid playmaker out of Peoria Central, and together they were going to make Bobby Hurley, Steve Wojciechowski and Jason Williams look like a warm-up act.

Livingston was that good.

“He had everything,” says Jason Kidd, who knows a thing or three about the craft of point guard. “He had all that energy. He could see the floor. He was unselfish. He could play all day. All of that, and he was 6-foot-7.”

Kidd smiles.

“You couldn’t draw up a more perfect blueprint,” he says.

The NBA thought so too, and in those days high school kids could still make the leap. Livingston leapt. Even then, Livingston’s mind worked two or three moves ahead of almost everyone else, just as a point guard’s mind must. His family wanted him to give Duke a try. Krzyzewski assured him the rigors of the ACC would make him more NBA ready. Livingston understood.

But the NBA people said he was likely to go less than an hour after the Magic made Dwight Howard the No. 1 pick overall and they were right: the Clippers took him at No. 4. And Livingston thought: How much higher will I go later?

“You never know what can happen,” he says. And then, without a whisper of irony, adds, “You can get hurt, you know?”

Understand this at the jump: the tragedy of Shaun Livingston is not a tragedy about Shaun Livingston. He has earned more than $23 million as a pro basketball player and is still only 28 years old. He has hungrily pursued every program the NBA offers: a broadcasting seminar at Syracuse last summer, a leadership forum in Las Vegas this offseason, a coaching clinic next year.

“It’s incredible what the league provides you in terms of leadership skills and life-after-basketball guidance if you just say, ‘Thank you’ and do it,” Livingston says. “More guys should take advantage of that.”

No, the tragedy is for basketball fans who saw stolen glimpses of what Livingston could do when he was young, barely out of his teens, precociously taking the moribund Clippers and making them impossibly fun to watch.

“Look, he wasn’t quite Magic,” Kidd says. “But he did stuff that sure reminded you of Magic.”

And then, in a YouTube moment that makes the Joe Theismann and Kevin Ware injuries look like kid’s cartoons, it was over: Feb. 26, 2007, a flight to the basket against the Warriors and a fall that, quite literally, tore his left knee apart. The injury was so horrific that a doctor at Los Angeles’ Centinela Hospital actually used the word “amputation” when she looked at it.

Six and a half years later, Shaun Livingston says: “It wasn’t the way I wanted my career to go. But it was clearly part of a plan.”

The journey from there to here was blinding: a trip to the D-League, stops in Miami, Oklahoma City, Washington (twice), Charlotte, Milwaukee. Finally an opportunity last year, backing up Kyrie Irving in Cleveland; Irving, who did play a year for Krzyzewski, though only for 11 games because of his own injury woes. Those 49 games opened a lot of eyes, including those of the Nets. In July, they signed him to a one-year deal at the league minimum to back up Deron Williams.

“It’s more than I could ever have dreamed of,” Livingston says. “Playing with a guy like [Williams]. Playing for a guy like Jason Kidd, who played my position as long and as well as it’s ever been played. And to be a part of a team with a real chance at success.”

All these years later, all those pit stops in between, Shaun Livingston looked around the Coach K Practice Court, at the rows of banners and retired numbers, at his own might’ve-been.

“Maybe if I come here, I get stronger, and better, and just because of circumstance I’m not where I was the night I got hurt,” Livingston says. “Or maybe something else happens. I don’t know. Nobody knows. You deal with what you get.”